Monthly Archives: October 2020

Turning crazy with sound

UPDATE: problem is still preset … still trying to find what is going on.

After a recent update on my debian workstation, I had spurious sound volume changes, only with line out, no matter my usb headset either plug in or out (but when I listen with the usb headset, there was no problem).

I did a few days of search, first is where to dig for a problem, then how to check pulse audio log, then how to check alsa, and acpi.

And the problem was … HARDWARE !

So the problem comes from spurious front jack headphone event as shown with the following logs. These plug/unplug event mess alsa and jack with volumes … maybe it can be fixed with some configuration to restore correct sound after unplug, but the problem is that I do not have front jack used at all.


(I use the explanation here to have pulseaudio log, tldr:

systemctl --user stop pulseaudio.socket #since the socket relaunch pulseaudio all the time.
echo autospawn = no >> ~/.config/pulse/client.conf 
LANG=C pulseaudio -vvvv --log-time=1 > ~/pulseverbose.log 2>&1
$ cat pulseverbose.log  | grep Jack | grep plug
(6391.015|   6.180) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
(6391.036|   0.018) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
(6476.288|  67.655) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in

$ sudo acpi_listen 
 jack/headphone HEADPHONE plug
 jack/headphone HEADPHONE unplug
 jack/headphone HEADPHONE plug
 jack/headphone HEADPHONE unplug

I tryied to plug/unplug an headset in the front jack, and the event do not coicinde … so I unplug the front jack from the motherboard, TADAA ! no more spurious event.

Next step is to check cable conductivity, and clean with contact cleaner, but nevermind, I do not use this jack anymore.

Take home message, sometimes events are related sometimes not … when dealing with computer events used to be linked (the update mess up a lot of things, because of gnome-shell update and incompatibility with some plugins), but this one was not, and it slow down a lot the resolution (since most of my net searches have gnome 3.38 in the key words, or debian update …) After a few days, I think of the problem differently, as how I can track what is going on rather than something is not correctly installed.

Internship proposal: Stroke clustering for stylized animation automatic in-betweening

Location : Laboratoire IRIT, STORM research team, Université Paul Sabatier – Toulouse

Advisor : David Vanderhaeghe,,, Amélie Fondevilla

Funding : ANR project Structures ANR-19-CE38-0009-01

Keywords : stroke-based rendering, painterly animation, example-based methods, computer graphics


Animation movies show great media of artistic expression (see Fig. [fig:ex]), allowing artists to convey powerful narrations, while not being limited to the existing range of shapes and motions. Unfortunately, they are significantly tedious and time consuming to produce. It is particularly the case for 2D animation composed of sets of marks, such as paint or drawings.

Standard stroke-based rendering methods can automatically produce stylized content made of marks such as paint strokes or hatching . They either focus on a specific style or technique to propose a fully automatic process, or allow to tweak style along larges sets of parameters , which may not be the more intuitive solution for an artist. They usually do not take into account style features related to motion, which is an important aspect of animation design .

Internship Project.

The high level goal of the project is to ease the creation of stroke based rendering animation, with the look and feel of hand made animation. One key question is how to capture user style and automatically create new frames of the animation. This kind of approach mixes an animated input (a 3D scene in our framework) with style information (digital painted frames in this proposal). The goal of the internship project is to analyze user created frames and generate intermediate frames in the same style. The first step is to define a metric to cluster strokes in a given frame. Theses clusters could be linked to an underlying 3D scene, which guides the animation. The second step is to create link the clusters extracted from two frames, and then provide a interpolation scheme to create in between frames.

Candidate’s profile.

Potential candidates for the thesis should have :

  • Master student in Computer Science, or equivalent.
  • Strong background in real time computer graphics, mathematics, and c++ programming.
  • Additional skills in some of the following topics would be appreciated: expressive rendering, user interface, numerical optimization.
  • Fluent french or english speaking.


Send your application to David Vanderhaeghe ( with

  • a complete CV,
  • high education grades report
  • reference name/email address


STORM is a research team part of the IRIT Laboratory (UMR CNRS 5505). We conduct research on computer graphics, including geometric modeling, 3D animation and rendering. See our webpage for more details about recent research The PhD will take place on the Rangueil campus, in the IRIT building, south of Toulouse, nearby all facilities and ground public transport to reach the city.